Cytogenetics- Microarray DNA analysis
CMH Lab Section
Microarray-based Comparative Genomic Hybridization (aCGH) or DNA microarray is a whole genome scanning method. In one single assay, the entire genome is evaluated for gains and/or losses of genomic regions as well as chromosomal aneuploidy.
Indications for postnatal aCGH testing include:
- Failure to thrive (FOT)
- Developmental Delay (DD)
- Mental retardation (MR)
- Multiple congenital anomaly (MCA)
- Dysmorphic features (DF)
- Autism or autism spectrum disorders (ASD)
- Congenital heart diseases (CHD)
- Learning disability
- Abnormal MRI/CT findings
- Muscular dystrophy
2-3 mL blood in EDTA lavender tube
Turn Around Time
Two (2) weeks for normal or preliminary abnormal results; three (3) weeks for confirmed abnormal results; and two (2) weeks for parental checking.
aCGH tests are performed using Agilent Human Genome Microarray Kit 244K (aCGH-244K). Quantitative real-time PCR (qPCR) technique is the primary method for the confirmation of abnormal copy number variants (CNVs) in patients and parental follow-up studies. FISH or chromosome GTG banding analyses will be recommended if a translocation is suspected.
Limitations: The Agilent aCGH-244K will not detect the following genomic abnormalities:
- Balanced chromosomal aberrations, such as balanced translocations;
- inversions or balanced insertions;
- Point mutations and genomic imbalances in regions that are not represented on the microarray;
- Low-level moasicism;
Each result report will have a brief description of aCGH finding. If an abnormal aCGH result is identified, a confirmation result, summarized interpretation, comprehensive comments, useful recommendation and related references will be provided.